Printers used in point-of-sale applications frequently need to have a paper supply reloaded by an operator who may be new to the job, or otherwise untrained. Moreover, it is often necessary that the paper be reloaded while customers are waiting to be served. Impact printers require close tolerances between the printhead and the platen. As a consequence, impact printers according to the prior art require the threading of paper through the printing mechanism, and a simultaneous manipulation of feed actuating mechanisms to load the paper in order that the relationship of the printhead and paper maintain the required tolerance. Moreover, the implementation of alternate paper feed paths in order to provide for the printing of form documents, as well as printing onto paper supplied in bulk, is difficult to implement in point-of-sale impact printers according to the prior art. The close tolerances between the printhead and the platen must be maintained in the presence of forms having different thickness paper. This is precluded in the impact printing mechanisms in printers having a platen and printhead with a fixed relative position, according to the prior art.
Thus, there is a need in the art for a mechanism that allows simple drop-and-load paper loading while maintaining tight head gap tolerances, and in which form thickness compensation is accommodated.